PiHKAL: A Chemical Love Story is a book by Dr. Alexander Shulgin and Ann Shulgin, published in 1991. The subject of the work is psychoactive phenethylamine chemical derivatives, notably those that act as psychedelics and/or empathogen-entactogens. The main title, PiHKAL, is an acronym that stands for "Phenethylamines I Have Known And Loved".
TiHKAL: The Continuation is a 1997 book written by Alexander Shulgin and Ann Shulgin about a family of psychoactive drugs known as tryptamines. A sequel to PIHKAL: A Chemical Love Story, TIHKAL is an acronym that stands for "Tryptamines I Have Known and Loved".
This leak is in PDF format and is linked below. Enjoy!